Semisolid A356 alloy feedstock poured through a serpentine channel

Fine spheroidal and equiaxed nondendritic microstructures required for semisolid casting can be formed through a serpentine pouting channel. Effects of the pouring temperature and the vertical section length of the serpentine pouring channel were studied. The results indicate that both favorable semisolid microstructures of A356 aluminum alloy can be generated by a serpentine pouring channel, and the solid shell inside the channel can be avoided when the pouting temperature is in the range from 660 to 680℃. It is also shown that the vertical section length of the serpentine pouting channel has a significant influence on the microstructure of the feedstock, namely both the microstructure of the feedstock and the microstructure uniformity in the radial direction get worse when the vertical section length is shortened; moreover, the pouring temperature for obtaining the feedstock with suitable microstructure decreases. The relevant mechanisms were discussed.

Exosomal mi R-182 regulates the effect of RECK on gallbladder cancer

BACKGROUND As the most common biliary malignancy,gallbladder cancer(GC)is an elderlybiased disease.Although extensive studies have elucidated the molecular mechanism of microRNA 182(miR-182)and reversion-inducing-cysteine-rich protein with kazal motifs(RECK)in various cancers,the specific role of exosomal miR-182 and RECK in GC remains poorly understood.AIM To explore the relationship between exosomal miR-182/RECK and metastasis of GC.METHODS Paired GC and adjacent normal tissues were collected from 78 patients.Quantitative polymerase chain reaction was employed to detect miR-182 and exosomal miR-182 expression,and Western blotting was conducted to determine RECK expression.In addition,the effects of exosomal miR-182/RECK on the biological function of human GC cells were observed.Moreover,the double luciferase reporter gene assay was applied to validate the targeting relationship between miR-182 and RECK.RESULTS Compared with normal gallbladder epithelial cells,miR-182 was highly expressed in GC cells,while RECK had low expression.Exosomal miR-182 could be absorbed and transferred by cells.Exosomal miR-182 inhibited RECK expression and promoted the migration and invasion of GC cells.CONCLUSION Exosomal miR-182 can significantly promote the migration and invasion of GC cells by inhibiting RECK;thus miR-182 can be used as a therapeutic target for GC.

Upregulation of miR-34c after silencing E2F transcription factor 1 inhibits paclitaxel combined with cisplatin resistance in gastric cancer cells

BACKGROUND MicroRNA 34c(miR-34c)has been reported to be associated with malignant types of cancer,however,it remains unknown whether miR-34c is involved in chemoresistance in gastric cancer(GC).AIM To investigate the effect of miR-34c and its upstream transcription factor E2F1 on paclitaxel combined with cisplatin resistance in GC cells.METHODS Paired GC tissues and adjacent normal tissues were randomly sampled from 74 GC patients.miR-34c and E2F1 were detected by real-time quantitative PCR(qPCR)and Western blot.In addition,the drug resistance of GC cells to paclitaxel and cisplatin was induced by concentration gradient increasing methods,and changes in miR-34c and E2F1 during this process were measured.Furthermore,E2F1 and miR-34c overexpression or underexpression vectors were constructed and transfected into drug-resistant GC cells.MTT was employed to test the sensitivity of cells to paclitaxel combined with cisplatin,qPCR was adopted to detect the expression of miR-34c,Western blot was applied to detect the expression levels of E2F1,drug resistance-related proteins and apoptosis-related proteins,and flow cytometry was used for the determination of cell apoptosis and cell cycle status.RESULTS E2F1 was overexpressed while miR-34c was underexpressed in GC.After inducing GC cells to be resistant to paclitaxel and cisplatin,E2F1 expression increased while miR-34c expression decreased.Both silencing E2F1 and overexpressing miR-34c could increase the sensitivity of drug-resistant GC cells to paclitaxel combined with cisplatin,promote cell apoptosis and inhibit cell proliferation.Among which,silencing E2F1 could reduce the expression of drug resistance-related proteins and apoptosis-related proteins,while over-expression of miR-34c could upregulate the expression of apoptosis-related proteins without affecting the expression of MDR-1,MRP and other drug resistance-related proteins.Rescue experiments demonstrated that inhibiting miR-34c could significantly weaken the sensitization of drug resistant cells,and Si E2F1 to paclitaxel combined with cisplatin.CONCLUSION E2F1 inhibits miR-34c to promote the proliferation of GC cells and enhance the resistance to paclitaxel combined with cisplatin,and silencing E2F1 is conducive to improving the efficacy of paclitaxel combined with cisplatin in GC cells.

Magnetic impurity in hybrid and type-Ⅱ nodal line semimetals

We study the Kondo screening of a spin-1/2 magnetic impurity in the hybrid nodal line semimetals(NLSMs) and the type-Ⅱ NLSMs by using the variational method. We mainly study the binding energy and the spin–spin correlation between magnetic impurity and conduction electrons. We find that in both the hybrid and type-Ⅱ cases, the density of states(DOS) is always finite, so the impurity and the conduction electrons always form bound states, and the bound state is more easily formed when the DOS is large. Meanwhile, due to the unique dispersion relation and the spin–orbit couplings in the NLSMs, the spatial spin–spin correlation components show very interesting features. Most saliently, various components of the spatial spin–spin correlation function decay with 1/r^(2) in the hybrid NLSMs, while they follow 1/r^(3) decay in the type-Ⅱ NLSMs. This property is mainly caused by the special band structures in the NLSMs, and it can work as a fingerprint to distinguish the two types of NLSMs.

Analgesic and anti-inflammatory activities and mechanisms of 70% ethanol extract of Zygophyllum macropodum in animals

Objective： To screen the preliminary phytochemical components, to investigate the acute oral toxicity, the analgesic and anti-inflammatory effects, and to analyze inflammatory factors on mice or rats of 70% ethanol extract of Zygopgyllurn macropodum aerial parts （ZME）. Methods： Preliminary phytochemical screening was carried out by color reaction. Acute oral toxicity was investigated by body weight, relative organ weight and other toxic signs. Acetic acid induced writhing and hot plate test were used to determine analgesic effect. Acetic acid induced vascular permeability and carrageenan induced paw edema were used to confirm anti-inflammation. Protein in pleural effu- sion, prostaglandin E2 （PGE2） and tumor necrosis factor alpha （TNF-a） in serum of pleuritic rats induced by carrageenan were analyzed to explore the action mechanisms. The test groups received ZME with 100, 300, 600 mg/kg, the positive control with aspirin （ASP） 200 mg/kg for mice, and ZME with 70, 210, 420 mg/kg and ASP 150 mg/kg for rats orally. The control （C） or negative control （NC） groups received 2% Tween 80 of 10 mL/kg orally. Results： ZME contain flavonoids, saponins, phenols and tannins, steroids, terpenoids, fats and oils, glycosides, carbohydrates, and reducing sugar, but no alkaloids. The lethal dose 50% （LD50） of ZME was greater than 2000 mg/kg and no toxic or deleterious effects and death during 14 d. Oral administration 300 and 600 mgJkg of ZME produced analgesic and anti-inflammatory effects significantly （P 〈 0.05 or P 〈 0.001） vs NC. It can reduce the writhing number, prolong the heat resisting time, suppress the permeability of the capillary wall increasing, mitigate the paw edema, reduce the content of protein in pleural effusion, and reduce PGE2 and TNF-α in blood. Conclusions： ZME possessed analgesic and anti-inflammatory activities which related to inhibit the production of protein, PGE2 and TNF-α. The LD50 of ZME treated orally to mice was greater than 2000 mg/kg.

Interface-correlated Characteristics of Stainless Steel/Carbon Steel Plate Fabricated by AAWIV and Hot Rolling

Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy （OM）, scanning electron mi- croscopy （SEM） and transmission electron microscopy （TEM）. The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/ CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interracial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.

Influence of hot rolling on microstructure and mechanical characteristics of explosive-welded FSS/CS laminate

The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate that by hot rolling, decarburization layer disappears and a uniform structure is gained in CS side, but ferrite grains and carbides in constituent FSS form an uneven band microstructure which is denser at superficial zone than near the interface. The transmission electron microscopy results indicate that the layers adhering to the interface show typical deformed microstructure features, i.e., stream-like strips and elongated grains in FSS plates, carbide precipitates and bended cementite fragments in CS plates; and high-density dislocations in both plates, With hot rolling, various mechanical strengths and hardness are increased, while the elongation percentage is diminished. Examination of fractographs from tensile tests reveals predominately small dimples for explosive-welded specimens, whereas both big dimples and cleavage fracture for rolled specimens. Stereomicroscopic fractographs taken on shear samples indicate that the surfaces of explosive-welded specimens exhibit uniform deformation, but uneven deformation is displayed for that of rolled specimens. These results indicate that hot rolling is beneficial to improve the strength of explosive-welded FSS/CS laminate but not good for enhancing its plasticity.